Patients with type 1 Diabetes mellitus who have been treated with MDI (Multiple Daily Injection) basal/bolus insulin, regular insulin/short acting insulin analogue + NPH insulin on a stable dose (no change more than 10 %) for at least 4 weeks prior to study entry, who have an HBA1c smaller/equal 9 % (measured at visit 1) and a BMI smaller/equal 35 kg/m2. In addition, patients must have a FBG value at day 1 before skipping meal (6:00 am - 07:00 am) between 90 - 120 mg/dl (5.0 - 6.5 mmol/l).